Total Magnetic Intensity (TMI) grid of (not used) survey  

Authors / CoAuthors

Geophysical Acquisition & Processing Section

Abstract

Total magnetic intensity (TMI) data measures variations in the intensity of the Earth magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This magnetic grid has a cell size of 0.001 degrees (approximately 100m). The data used to produce this grid was acquired in 2000 by the SA Government, and consisted of UNKNOWN line-kilometres of data at 300.0m line spacing and 80.0m terrain clearance.

Product Type

dataset

eCat Id

105474

Contact for the resource

Keywords

( Theme )

• TMI

( Theme )

• magnetics

( Theme )

• NCI

( Theme )

• AU

( Theme )

• Magnetism and Palaeomagnetism

( Theme )

• Airborne Digital Data

( Theme )

• Geophysical Survey

( Theme )

• grid

( Project )

• 2010

• Published_Internal

Publication Date

2011-01-01T00:00:00

Creation Date

Security Constraints

Australian Government Security ClassificationSystem    

Classification - unclassified

Legal Constraints

Status

Purpose

Maintenance Information

notPlanned

Topic Category

geoscientificInformation

Series Information

Lineage

This mSA2010.nc grid is an airborne-derived Total Magnetic Intensity (TMI) grid for the (not used) survey. The survey was acquired under the project No. 2010 for the geological survey of SA. The grid has a cell size of 0.001 degrees (approximately 100m). A total of UNKNOWN line-kilometres of data at a line spacing of 300.0m were acquired to produce this grid. To constrain long wavelengths in the grid, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey grid (Milligan et al., 2009). This survey grid is essentially levelled to AWAGS. Details of the specifications of individual airborne surveys can be found in the Fourteenth Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). This Index is also available online at https://pid.geoscience.gov.au/dataset/ga/79134. Further up to date information about individual surveys can also be obtained online from the Airborne Surveys Database at http://www.ga.gov.au/oracle/argus/. The original grid was converted from ERMapper (.ers) format to netCDF4_classic format using GDAL1.11.1. The main purpose of this conversion is to enable access to the data by relevant open source tools and software. The netCDF grid was created on 2016-10-26T14:07:50. References Milligan, P.R., Minty, B.R.S., Richardson, M. & Franklin, R., 2009. The Australia-wide Airborne Geophysical Survey accurate continental magnetic coverage. Preview, No. 138, p. 1-128. Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition).

Parent Information

Geophysical Data Collection - magnetics

UUID - c6b58f54-102e-19e9-e044-00144fdd4fa6,

eCat ID - 74514

Extents

[-28.853001, -28.231001, 136.271501, 135.810501]

Reference System

WGS 84 (geocentric) (EPSG:4328)

Spatial Resolution

Service Information

Associations

Downloads and Links

Source Information

This mSA2010.nc grid includes airborne-derived TMI data for the (not used) survey acquired for the geological survey of SA